decided to just make a new thread regarding this since it's good info for those new to this game.

There are two differences in "raiding with tickets" and "fighting normally"

first difference
you can only use raid tickets when you have achieved 3 stars for that particular stage. This applies to both normal and elite dungeon maps.

second difference
in a normal "fighting normally" stage, your exp gained is split among all the active heroes used in that particular fight. However, if you use raid tickets, you'll notice that you won't be getting hero exp. Your heroes do not level up this way, instead, you'll be given exp potions. These exp potions can be used to boost a hero's exp tremendously, instead of spreading out your exp points over your active heroes in the fight. Also take note that you can choose to use 5 or less heroes in any battle. You'll definitely be getting more exp if you use less than your 5 hero's in a fight, but it'll depend if you can actually win the fight with less than 5 hero's it's a good way to boost your hero's xp without the use of xp potions.

Here's an analysis of this that i experimented with. Hope it helps you understand.